 (defn lexemes-before-phrases [depth]
   ;; takes depth as an argument; make phrases decreasingly likely as depth increases.
   (let [result (> (rand-int (+ 1 depth)) 0)]
-    (log/debug (str "lexemes-before-phrases: depth=" depth " => " result))
+    (log/trace (str "lexemes-before-phrases: depth=" depth " => " result))
     result))
 
 ;; TODO: add usage of rule-to-lexicon cache (rather than using lexicon directly)

                      (let [candidate-lexemes (get-lex parent :head index spec)]
                        (if (some fail? candidate-lexemes)
                          (exception (str "some candidate lexeme was fail?=true!")))
                        (log/debug (str "lightning-bolt: depth=" depth "; getting lexical heads for rule: " (get-in parent [:rule])))
                        (over/overh parent
                                    (map copy (lazy-shuffle candidate-lexemes))
                                    morph))))

            (mapcat (fn [parent]
                      (if (nil? (get-in parent [:head] nil))
                        (exception "get-in(parent,:head) was nil before looking for phrasal heads."))
                      (over/overh parent (lightning-bolt grammar lexicon (get-in parent [:head])
                                                         (+ 1 depth) index morph)
                                  morph))
